refactor(blogo,fs): move fs code to it's own package

blogo/fs/fs.go

@@ -13,12 +13,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package blogo
+package fs
 
 import (
 	"io/fs"
 )
 
+var ErrNotExist = fs.ErrNotExist
+
 type FS interface {
 	Metadata() Metadata
 	Open(name string) (File, error)

blogo/fs/metadata.go

@@ -13,7 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package blogo
+package fs
 
 import "errors"